A coach house on Chicago’s Northwest Side. [Lichter Realty]

Chicago property owners have applied to build 361 new basement or attic apartment buildings and 166 new backyard coach houses in the approximately one year since their construction has been legal, city officials said Monday as they weigh whether they should accelerate the legalization push. But while some aldermen point to the numbers as a sign that the new homes — known as Accessory Dwelling Units or Additional Dwelling Units (ADUs) — have been a success, others remain skeptical.